This is a first for me. Actually, it’s the first time I’ve fermented a lager at proper temps. But, what happened was rather peculiar. My Dutch Lager yeast was pitched at room temperatures (learned that’s the incorrect way to do it). Moved to cool location the next day after fermentation started. Temps dropped to around 57 degrees F the following day, where the air lock plopped every 3 seconds. Then, to 52 F. the next day where the air-lock plopped every 5 seconds. The next day during the morning it was once every 15 seconds at 50 F., indicating fermentation was slowing. I checked it 5 hours later and it had increased in activity to once every 5 or 6 seconds, still at 50 F. How is this possible? There has been no change in temp. Is this normal for lagers?
Just remember that airlock activity does not indicate fermentation activity. There could be all sorts of things going on with it, particularly if the temp of the beer changed.
If you pitched warm on a lager, not a huge deal, but remember the yeast will produce increased diacetyl when pitched warm, so make sure when the fermentation is about 2/3 done (have to measure gravity) to raise the temp a few degrees per day until it gets up to 65 or so to clean up that additional diacetyl.
[quote=“Pietro”]Just remember that airlock activity does not indicate fermentation activity. There could be all sorts of things going on with it, particularly if the temp of the beer changed.
If you pitched warm on a lager, not a huge deal, but remember the yeast will produce increased diacetyl when pitched warm, so make sure when the fermentation is about 2/3 done (have to measure gravity) to raise the temp a few degrees per day until it gets up to 65 or so to clean up that additional diacetyl.[/quote]
Thanks, Pietro. I actually read about diacetyl dilemmas the day afer I pitched, and that’s what John said about the off flavor. But, he didn’t mention anything about moving it to a warmer enviroment to clean up the diacetyl. I’ll give it a try and see what happens. Appreciate that info. I wonder if it would be ok to do this when I move the brew to the secondary? I plan to drop hop it at that time anyway. What do you think?
My personal preferance with lagers, is do my Diacetyl rest, then leave it in primary for another week or two before racking to a carboy for lagering. My understanding is that all stages of primary fermentation should be complete before starting the lagering process.
good advice. Seconded. Diacetyl rests need to be done when the beer is still on the yeast.
Appreciate the advice, everyone. The brew has fermented for a week now and is still fairly active. Temperature has fallen to around 40 F.
